We're talking about a news organization responsible for leaking US secrets, with it's head using the asylum of an embassy to prevent extradition on crimes he says are politically motivated, releasing hacked emails in an attempt to disrupt a presidential candidacy. This was using the official twitter channel for Wikileaks. I'm not sure what part of that lends itself to joking, and even if it did, an anti-semitic one isn't what I would consider appropriate for a organization such as that, and would need to be addressed specifically. Even on twitter.
Also, how it that funny? Using Jewish stereotypes and anti-semitic labeling to imply your critics are Jews trying to climb the social ladder? Is that supposed to pass for humor? Maybe next he'll make some comment about a group of people with no jobs, having great tans, and that just love to eat fried chicken and watermelon. What a comedian, that guy.
Then why do I see self proclaimed jews on twitter with the walls? I though it was a joke.... Considering it's... twitter.